Hand held paint spray guns are commonly operated with an attached paint cup. Typically, a threaded nipple depends from the gun body adjacent a nozzle for receiving paint from either a paint cup or a pressurized paint supply hose. The paint cup has a lid assembly from which the cup is removable for filling and cleaning the cup. The lid assembly includes a lid for closing the top of the paint cup and a yolk which releasably engages pins projecting from opposite sides of the cup adjacent the top. When the yolk engages the pins, a lever actuated cam is rotated for locking the lid onto the cup. A paint feed tube secured to the lid extends from the bottom of the cup through the cam and the yolk and is secured by a nut to the paint gun nipple. Or, the lid assembly may be retained on the cup pins by other known means, such as by the force of a spring located between the lid and the yolk.
In many paint spray guns, the paint flows from the cup to the gun through suction feed. For successful suction feed, it is necessary to vent the paint cup to atmosphere. The vent is normally in the paint cup lid and must be designed and located to prevent dripping when the spray gun is tipped, for example, when painting a horizontal surface. Consequently, the orientation of the vent relative to the gun is important. In order to maintain a desired vent location, the lid and yolk of the lid assembly are prevented from rotating relative to the paint feed tube secured to the gun. A wrench is required in order to secure the paint cup lid assembly to the spray gun and to remove the lid assembly from the spray gun. At times, it is desirable to be able to attach the lid assembly to a spray gun or to remove the cup and lid assembly from the spray gun without the use of a separate wrench.